Re: Switch lamp

I don't know what is acceptable, but if you are willing to drill a hole in the switchstand post that's large enough for a padlock, you could take two angle brackets (thin), put them together oriented in the same direction with one leg touching and the other spaced wide enough apart that you could slip it onto the base of your lantern. This would make a bracket that could fill the gap between the hole in the lantern and the switchstand post. You could then drill a hole in the joined legs of the bracket to line up with the hole in the switchstand post and just lock the bracket/lantern to the post.
If you aren't willing to drill the switchstand post, you will probably need some kind of bracket that can be tightened sufficiently to clamp onto the post and then locked into its tightened position (something like a drill chuck that can not be loosened without your key?).
Good luck! Sounds like a nice nighttime touch.